Leandru-Gheorghe BUJOREANU

Universitatea Tehnica GHEORGHE ASACHI din Iasi, Iasi, .

E-mail: trimite un mesaj.

Pagina web a instituţiei: http://www.tuiasi.ro
Pagina web personala: http://www12.tuiasi.ro/facultati/sim/index.php?page=891

Urmareste linkul ResearcherID pentru toate articolele cercetatorului: G-1268-2010. Tabelul detaliat al articolelor este in josul paginii.

Nascut(a) in: 1959

Interese: aliaje cu memoria formei, materiale nemetalice cu memoria formei, transformarea martensitica, frecare interna, modificari structurale, analiza termica, comportament la tractiune, microstructura, cristalografie, tratamente termice, superaliaje, fluide electro si magnetoreologice, prelucrare cu ultrasunete

Detalii:
Activitatea de cercetare a fost concentratã pe 3 domenii: 1-efectele expunerii prelungite la presiuni şi temperaturi ridicate; 2-efectele ultrasunetelor asupra deformãrii plastice şi a sudãrii şi 3-prelucrarea, caracterizarea şi dezvoltarea aliajelor cu mmeoria formei (AMF), incluzând cele patru sisteme comerciale principale, bazate pe: a) Cu-Al-Ni; b) Cu-Zn-Al; c) Ni-Ti şi d) Fe-Mn-Si.
a) Rezultatele cercetãrilor privind AMF pe bazã de Cu-Al-Ni sunt vizibile prin intermediul studiilor asupra superelasticitãţii cu curgere dublã, publicate în românã în 1994 în revista Metalurgia şi în englezã, în 1995, în revista Cercetãri Metalurgice şi de Noi Materiale. În 1994 a fost editat în colaborare brevetul de invenţie nr. 111855/ 1994 referitor la procedura de obţinere a unui AMF Cu-Al-Ni-Fe-Sn. La nivel internaţional, au fost prezentate o serie de rapoarte focalizate pe: (i) reversibilitatea martensitelor induse termic şi mecanic în AMF Cu-Al-Ni-Mn-Fe (Mat Sci Eng A, 481-482 494 2008); (ii) morfologia precipitatelor din AMF Cu-Al-Mn (J Optoelectron Adv M 10(6) 1365 2008) şi pe efectele fazei alfa;2 asupra memoriei termice (ESOMAT 05004, 2009). A fost de zvoltatã o tehnicã originalã de prelucrare pentru turnarea cu model fuzibil a resorturilor elicoidale (Optoelectron Adv Mat 3(6) 581 2009, prezentare oralã la SMST 2008).
b) Activitatea dce cercetare referitoare la AMF pe bazã de Cu-Zn-Al a început cu susţinerea publicã tezei de doctorat, care a prezentat o tehnologie originalã de prelucrare a lamelelor laminate la cald şi cãlite instantaneu. Primele rezultate de cercetare au fost publicate în românã şi au constat dintr-o carte despre memoria termicã şi mecanicã a AMF Cu-Zn-Al SMA şi din mai multe lucrãri publicate în revista Metalurgia journal, începând din 1996, asupra diferitor subiecte cum ar fi dependenţa parameterilor pseudoelastici de istoriile termicã şi mecanicã. În englezã, au fost publicate lucrãri în revista româneascã Cercetãri Metalurgice şi de Noi Materiale şi în seria Advances in Micro- and Nanoengineering, raportând: (i) o metodã de producere şi educare actuatorilor electrici; (ii) efecte tratamentului termic într-un AMF experimental Cu-Zn-Al SMA şi (iii) transformãri microstructurale care însoţesc apariţia şi stabilizarea memorie termice. La nivel internaţional, un capitol despre formarea tranzitorie a bainitei, ca un precursor al fazei alfa;, a fost inclus într-o carte publicatã de Nova Science Publishing, în 2010, în timp ce principalele rezultate de cercetare au fost legate de: (i) formarea preferenţialã a fazei alfa; (J All Compd 278, 190 1998); (ii) modificãrile induse termic şi prin tensiune într-un AMF cu structurã tri-fazicã (Mater Sci Tech-Lond 16 612 2000); (iii) influenţa austenitizãrii asupra morfologiei fazei α şi studiul efectului de memoria formei (EMF) în resorturi lamelare elicoidale (Mat Sci Eng A 481-482 395 2008, prezentare oralã la ESOMAT 2006); (iv) influenţa factorilor extrinseci asupra EMF în dublu sens (J Optoelectron Adv M 10(3) 602 2008, prezentare sub formã de poster la EUROMAT 2007); (v) degradarea memoriei termice în timpul ciclãrii termice cu rãcire în aer liber (J Mater Eng Perform, 20(3) 468 2011).
c) rezultatele de cercetare referitoare la AMF NiTi au raportat unele efecte de tratament tremic asupra comportãrii la tracţiune a unui AMF Ni50.7Ti49.3 legate de precipitarea de Ni4Ti3 (Int J Mater Res, 101(5) 623 2010).
d) Principalele rezultate de cercetare asupra AMF pe bazã de Fe-Mn-Si sunt datorate colaborãrii cu Dr. Takahiro SAWAGUCHI de la NIMS Tsukuba şi includ: (i) efecte de blocare asupra frecãrii interne legatã de transformare a Fe-17Mn (ISIJ Inter, Vol. 48 (1) 99 2008, Spring Meeting de la Japan Institute of Metals, 26-28 March 2008, secţiunea S2, Structural and Functional Materials Utilizing Displacive Transformations, http://www.sendai.kopas.co.jp/METAL/MEETINGS/2008_spr/PRO/27_k.html) şi (ii) mecanismul plasticitãţii reversibile indusã prin transformare în Fe-Mn-Si (Scripta Mater 59(10), 826 2008). În cadrul a 3 proiecte de cercetare conduse, ca director, (Grant A nr. 476, 2004-2005; Grant A nr.275, 2006-2007 şi PN-II-ID-PCE-1 nr. 301, 2007-2010) finanţate cu 66.000; 138.000 şi respectiv 726.788 RON, de cãtre Unitatea Executivã pentru Finanţarea Învãţãmântului Superior şi a Cercetãrii Stiinţifice Universitare, s-au obţinut patru rezultate de cercetare importante, referitoare la: (i) comportamentul de revenire reţinutã al Fe-Mn-Si (Eur Phys J-Spec Top, 158 15 2008, prezentare oralã la E-MRS Fall 2007) şi al Fe-Mn-Si-Cr-Ni, în timpul ciclãrii termice (Optoelectron Adv Mat, 4(6) 816 2010); (ii) factorii care influenţeazã reversia martensitei induse prin tensiune în austenitã la in Fe-Mn-Si-Cr-Ni (J Mater Eng Perform 18(5-6) 500 2009); (iii) un studiu comparativ al structurilor aliajelor Fe-Mn-Si-Cr-Ni obţinute prin metalurgie clasicã şi metalurgia pulberilor (ESOMAT 05003 2009) şi (iv) efecte de ciclare mecanicã la AMF Fe-Mn-Si-Cr-Ni obţinute prin metalurgia pulberilor (Physics Procedia 10 125 2010).
Vizibilitatea contrbuţiilor ştiinţifice. A. Prezentãri orale la conferinţe internaţionale: 1) ESOMAT 2006, Bochum/ Germania 10-15 Septembrie; 2) E-MRS Fall Meeting 2007 Warsaw/ Polonia 17-21 Septembrie; 3) SMST2008 Stresa/ Italia 21-25 Septembrie şi 4) ESOMAT2009 Praga/ Republica Cehã 7-11 Septembrie. B. Cursuri susţinute la Universitatea Tehnicã Istanbul: 1) Rolul transformãrii martensitice asupra fenomenelor de memoria formei, 2.11.2007; 2) Efectul de memoria formei cu revenire reţinutã în aliaje, 9.11.2007; 3) Efecte calorimetrice asociate cu reversia martensitei în aliajele cu memoria formei pe bazã de Cu, 11.05.2010; 4) Formarea tranzitorie a bainitei ca precursor al fazei alfa; în AMF revenite, 12.05.2010; 5) Asupra reacţiei termomecanice a aliajelor cu memoria formei pe bazã de Fe, 13.05.2010. C. Membru al Comitetului Stiinţific Internaţional al Celui de-al 15lea Congres Internaţionla de Metalurgie şi Materiale IMMC2010 http://www. metalurji.org.tr/congress/. D. Capitol invitat în cartea "Shape Memory Alloys: Manufacture, Properties and Applications", Editatã de H.R. Chen, Nova Science Publishers 2010: Formation of transitory bainite as a precursor of alpha-phase during tempering of mastensitic Cu-Zn-Al SMAs https://www. novapublishers.com/catalog/advanced_search_result.php?keywords=bujoreanu&os Csid=aee701 cf1ca1ce6c9f88f5f412a7e758. E. Referent voluntar pentru revista J Mater Eng Perform (3 recenzii-2008, 2-2009, 3-2010), Mat Sci Eng A (2 rec.-2010), J Appl Polym Sci (1 rec.-2010, 1-2011), precum şi pentru J Alloy Compd, Mater Sci Eng B şi Smart Mater Struct -1 recenzie fiecare. F. Membru al biroului Comisiei "Ingineria Materialelor şi Nanotehnologii" a Consiliului Naţional de Atestare a Titlurilor, Diplomelor şi Certificatelor Universitare numit pentru 4 ani, în 2011.

Details:
Research activity has been focused on 3 domains: 1-prolonged exposure effects to high temperatures and pressures; 2-ultrasonics effects on plastic deformation and on welding and 3-processing, characterization and development of shape memory alloys (SMAs), comprising the four main commercial alloy systems, based on: a) Cu-Al-Ni; b) Cu-Zn-Al; c) Ni-Ti and d) Fe-Mn-Si.
a) The research results concerning Cu-Al-Ni base SMAs have been visible by means of the studies on double-yield superelasticity, published in Romanian in 1994 in the journal Metalurgia, and in English in 1995 in the journal Metallurgy and New Materials Researches. In 1994, patent no. 111855/ 1994 was co-authored concerning the obtaining procedure of Cu-Al-Ni-Fe-Sn SMA. At international level, PL some reports were co-authored focusing on: (i) the reversibility of thermally and stress induced martensites in Cu-Al-Ni-Mn-Fe SMAs (Mat Sci Eng A, 481-482 494 2008); (ii) precipitate morphology in Cu-Al-Mn SMAs (J Optoelectron Adv M 10(6) 1365 2008) and on the effects of γ2-phase upon thermal memory (ESOMAT, 05004 2009). An original processing technique was developed for helical springs' investment casting (Optoelectron Adv Mat 3(6) 581 2009, oral presentation at SMST 2008).
b) Research activity concerning Cu-Zn-Al base SMAs started with public defense of the PhD thesis which introduced an original manufacturing technology of hot rolled-instantly quenched lamellas. First research results were published in Romanian and consisted in a printed book on thermal and mechanical memory of Cu-Zn-Al SMA and in several papers published in Metalurgia journal, since 1996, on various topics such as dependence of pseudoelasticity parameters on the mechanical and thermal histories. In English, papers were published in Romanian journals Metallurgy and New Materials Researches and in the series Advances in Micro- and Nanoengineering, reporting: (i) a method for producing and training electrical actuators; (ii) heat treatment effects in an experimental Cu-Zn-Al SMA and (iii) microstructural changes accompanying thermal memory occurrence and stabilization. At international level, a chapter on bainite transitory formation, as a precursor of α-phase, was included in a book published by Nova Science Publishing, in 2010 while the main research results have been related to: (i) preferred formation of the α-phase (J All Compd 278, 190 1998); (ii) thermally and stress induced changes in three phase structure SMA (Mater Sci Tech-Lond 16 612 2000); (iii) influence of austenitization on α-phase morphology and shape memory effect (SME) study in lamellar helical springs (Mat Sci Eng A 481-482 395 2008, oral presentation at ESOMAT 2006); (iv) influence of extrinsic factors on the two way SME (J Optoelectron Adv M 10(3) 602 2008, poster presentation at EUROMAT 2007); (v) thermal memory degradation during thermal cycling with free air cooling (J Mater Eng Perform, 20(3) 468 2011).
c) the research results concerning NiTi SMAs reported some heat treatment effects on the tensile behavior of a Ni50.7Ti49.3 SMA related to the precipitation of Ni4Ti3 (Int J Mater Res, 101(5) 623 2010).
d) The main research results on Fe-Mn-Si base SMAs are due to the collaboration with Dr. Takahiro SAWAGUCHI from NIMS Tsukuba and comprise: (i) pinning effects on the transformation-related internal friction of Fe-17Mn (ISIJ Inter, Vol. 48 (1) 99 2008, Spring Meeting of the Japan Institute of Metals, 26-28 March 2008, section S2, Structural and Functional Materials Utilizing Displacive Transformations, http://www.sendai.kopas.co.jp/METAL/MEETINGS/2008_spr/PRO/27_k.html) and (ii) the mechanism of reversible transformation-induced plasticity in Fe-Mn-Si (Scripta Mater 59(10), 826 2008). Within 3 research projects run as a director (Grant A no. 476, 2004-2005; Grant A no.275, 2006-2007 and PN-II-ID-PCE-1 no. 301, 2007-2010) financed with 66,000; 138,000 and 726788 RON, respectively, by Romanian Executive Agency for Higher Education, Research Development and Innovation, four significant research results were obtained concerning: (i) tensile constrained recovery behavior of Fe-Mn-Si (Eur Phys J-Spec Top, 158 15 2008, oral presentation at E-MRS Fall 2007) and of Fe-Mn-Si-Cr-Ni, during thermal cycling (Optoelectron Adv Mat, 4(6) 816 2010); (ii) the factors influencing the reversion of stress-induced martensite to austenite in Fe-Mn-Si-Cr-Ni (J Mater Eng Perform 18(5-6) 500 2009); (iii) a comparative study of Fe-Mn-Si-Cr-Ni structures obtained by classical and by powder metallurgy (ESOMAT 05003 2009) and (iv) mechanical cycling effects at Fe-Mn-Si-Cr-Ni SMAs obtained by powder metallurgy (Physics Procedia 10 125 2010).
The visibility of the scientific contributions. A. Oral presentations at international conferences: 1) ESOMAT 2006, Bochum/ Germany 10-15 September; 2) E-MRS Fall Meeting 2007 Warsaw/ Poland 17-21 September; 3) SMST2008 Stresa/ Italy 21-25 September and 4) ESOMAT2009 Prague/ Czech Republic 7-11 September. B. Lectures at Istanbul Technical University: 1) The role of martensitic transformation on shape memory phenomena, 2.11.2007; 2) Constrained recovery shape memory effect in alloys, 9.11.2007; 3) Calorimetric effects associated with martensite reversion in Cu-base shape memory alloys, 11.05.2010; 4) Transitory formation of bainite as a precursor of α-phase in tempered SMAs, 12.05.2010; 5) On the thermomechanical response of Fe-base shape memory alloys, 13.05.2010. C. Member of International Scientific Committee at 15th International Metallurgy & Materials Congress IMMC2010 http://www. metalurji.org.tr/congress/. D. Invited chapter in "Shape Memory Alloys: Manufacture, Properties and Applications", Ed. H.R. Chen, Nova Science Publishers 2010: Formation of transitory bainite as a precursor of α-phase during tempering of mastensitic Cu-Zn-Al SMAs https://www. novapublishers.com/catalog/advanced_search_result.php?keywords=bujoreanu&os Csid=aee701 cf1ca1ce6c9f88f5f412a7e758. E. Voluntary reviewer for J Mater Eng Perform (3 revs.-2008, 2-2009, 3-2010), Mat Sci Eng A (2 revs-2010), J Appl Polym Sci (1 rev-2010, 1-2011), as well as for J Alloy Compd, Mater Sci Eng B and Smart Mater Struct -1 review each. F. Member of the bureau of the Commission "Materials Engineering and Nanotechnology" of the National Council of Attestation of University Titles, Diplomas and Certificates nominated for 4 years, in 2011.

Publicații selectate:

* Marius-Gabriel Suru, Adrian-Liviu, Paraschiv, Nicoleta Monica Lohan, Bogdan Pricop, Burak Ozkal, Leandru-Gheorghe Bujoreanu, Loading Mode and Environment Effects on Surface Profile Characteristics of Martensite Plates in Cu-Based SMAs, Journal of Materials Engineering and Performance, 23(7), 2014.

* GURÃU, Gheorghe, GURÃU, Marlen, POTECAŞU, Octavian, ALEXANDRU, Petricã, Bujoreanu, Leandru, Novel high speed high pressure torsion technology for obtaining Fe-Mn-Si-Cr shape memory alloy active elements, Journal of Materials Engineering and Performance, 23(7), 2014.

* A. Umut Söyler, Burak Özkal and Leandru G. Bujoreanu, Improvement of shape memory characteristics of Fe-14Mn-6Si-9Cr-5Ni powder metallurgy alloy via mechanical alloying, Journal of Materials Engineering and Performance, 23(7), 2014.

* G. Gurãu, C. Gurãu, F. M. Braz Fernandes, L. G. Bujoreanu, An Experimental Study on the Response of Equal Channel Angular Pressed Aluminum Subjected to Cold Rolling, Indian Journal of Engineering and Materials Sciences, 21(3), 2014.

* M.-G. SURU, C. MOROŞANU, L.-G. BUJOREANU, Variation tendencies of shape memory alloys surface relief as a function of training-cycling parameters, JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, Vol. 16, No. 3-4, March - April, 2014.

* B. PRICOP, B. ÖZKAL, U. SÖYLER, J. VAN HUMBEECK, N. M. LOHAN, M. G. SURU, L.-G. BUJOREANU, Influence of mechanically alloyed fraction and hot rolling temperature in the last pass on the structure of Fe-14Mn-6Si-9Cr-5Ni (mass. %) shape memory alloys processed by powder metallurgy, OPTOELECTRONICS AND ADVANCED MATERIALS – RAPID COMMUNICATIONS, Vol. 8, No. 3-4, 2014.

* M.-G. Suru, I. Dan, N. M. Lohan, A. L. Paraschiv, B. Pricop, I. P. Spiridon, C. Baciu, L.-G. Bujoreanu, Effects of hot working procedure on surface relief characteristic in an Fe–Mn–Si–Cr shape memory alloy, WILEY, Materialwissenschaft und Werkstofftechnik, 45(1), 2014.

* A. L. PARASCHIV, F. BORZA, M.-G. SURU, B. PRICOP, I. P. SPIRIDON, E. MIHALACHE, L.-G. BUJOREANU, Chemical composition and processing effects on the pseudoelastic response of α’ ferromagnetic martensite, OPTOELECTRONICS AND ADVANCED MATERIALS – RAPID COMMUNICATIONS, Vol. 7, No. 11-12,, 2013.

* A.-L. PARASCHIV, F. BORZA, N. LUPU, M.-G. SURU, N. M. LOHAN, B. PRICOP, I.-P. SPIRIDON, L.-G. BUJOREANU, On some structural characteristics of Fe-base shape memory alloys, JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, Vol. 15, No. 7-8, July - August, 2013.

* I. P. SPIRIDON, B. PRICOP, M. G. SURU, A. L. PARASCHIV, N. M. LOHAN, L-G. BUJOREANU, The influence of heat treatment atmosphere and maintaining period on the homogeneity degree of a Fe- Mn-Si-Cr-Ni shape memory alloy obtained through powder metallurgy, JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, Vol. 15, No. 7-8, July - August, 2013.

* L. G. BUJOREANU, M.L.CRAUS, V.DIA and V.PLUGARU, RESPONSE TO APPLIED MECHANICAL LOAD OF A MULTIVARIANT MARTENSITIC Cu-Zn-Al-Fe SHAPE MEMORY ALLOY, University Politehnica of Bucharest, Scientific Bulletin, Series B: Chemistry and Materials Science, 64(3), 2002.

* M. G. SURU, A. L. PARASCHIV, B. PRICOP, L. G. BUJOREANU, A statistical evaluation of thermomechanical loading effects on martensite plate morphology in CuZnAl SMAs, OPTOELECTRONICS AND ADVANCED MATERIALS – RAPID COMMUNICATIONS, 7(1-2), 2013.

* Bogdan Pricop, Umut Söyler, Burak Özkal, Nicoleta Monica Lohan, Adrian Liviu Paraschiv, Marius Gabriel Suru and Leandru-Gheorghe Bujoreanu, Influence of mechanical alloying on the behavior of Fe-Mn-Si-Cr-Ni shape memory alloys made by powder metallurgy, Sergey Prokoshkin and Natalia Resnina, Materials Science Forum, 738-739, 2013.

* Gigi Vitel, Marius Suru, Adrian Paraschiv, Nicoleta Lohan, Bogdan Pricop, Maria Baciu & Leandru Bujoreanu, Structural Effects of Training Cycles in Shape Memory Actuators for Temperature Control, Taylor & Francis, Materials and Manufacturing Processes, 28(1), 2012.

* M.-G. Suru, L.-G. Bujoreanu, Comparative topographic study of surface micro-relief of primary martensite plates in shape memory alloys with different crystalline structures, WILEY-VCH Verlag GmbH & Co. KGaA,Weinheim, Materialwissenschaft und Werkstofftechnik, 43, No. 11, 2012.

* N.M. Lohan, L.-G. Bujoreanu, C. Baciu, Influence of temperature variation rate on calorimetric response during heating and on martensite structure obtained after subsequent cooling of Cu-Zn-Al shape memory alloy, The Institution of Engineering and Technology, Micro & Nano Letters, Vol. 7, Iss. 6, 2012.

* A. Umut Söyler, Burak Özkal, Leandru G. Bujoreanu, Investigation of Mechanical Alloying Process Parameters on Fe-Mn-Si Based, Wiley, TMS (The Minerals, Metals & Materials Society), February 27–March 3, in San Diego, California, U.S.A., Supplemental Proceedings: Volume 1: Materials Processing and Energy Materials, 2011.

* G. Vitel, A. L. Paraschiv, M. G. Suru, N. Cimpoesu, L.-G. Bujoreanu, Tempering effects in a normalized hot forged Cu-Zn-Al shape memory alloy, Optoelectronics and Advanced Materials-Rapid Communications, 6(1-2), 2012.

* B. Pricop, U. So¨ yler, N.M. Lohan, B. O¨ zkal, L.G. Bujoreanu, D. Chicet, and C. Munteanu, Thermal Behavior of Mechanically Alloyed Powders Used for Producing an Fe-Mn-Si-Cr-Ni Shape Memory Alloy, Springer, Journal of Materials Engineering and Performance, 21(11) DOI: 10.1007/s11665-012-0168-5, 2012.

* L.-G. Bujoreanu; N. M. Lohan; B. Pricop; N. Cimpoeşu, On role of atomic migration in amnesia occurrence during complex thermal cycling of Cu-Zn-Al shape memory alloy, Maney Publishing, Materials Science and Technology, 28(6), 2012.

* Sergiu Stanciu, Leandru G. Bujoreanu, Iulian Ioniţã, Andrei V. Sandu and Alexandru Enache, A structural-morphological study of a Cu63Al26Mn11 shape memory alloy, SPIE, Bellingham, WA, 2009, Paul Schiopu, Cornel Panait, George Caruntu, Adrian Manea, Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies IV, Proceedings of SPIE, 7297, 2009.

* Leandru G. Bujoreanu, Sergiu Stanciu, Paul Bârsãnescu, Nicoleta M. Lohan, Study of the transitory formation of α1 bainite, as a precursor of α-, SPIE, Bellingham, WA, 2009, Paul Schiopu, Cornel Panait, George Caruntu, Adrian Manea, Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies IV, Proceedings of SPIE, Vol. 7297, 2009.

* Nicoleta Monica Lohan, Bogdan Pricop, Leandru-Gheorghe Bujoreanu, Nicanor Cimpoesu, , Heating rate effects on reverse martensitic transformation in a Cu–Zn–Al shape memory alloy, International Journal of Materials Research, 102(11), 2011.

* G. Vitel, A. L. Paraschiv, M. G. Suru, N. Cimpoesu, L.-G. Bujoreanu, New calorimetric-structural aspects of temperature memory effect in hot rolled Cu-Zn-Al SMAs, Optoelectronics and Advanced Materials-Rapid Communications, 5(8), 2011.

* Pricop, U. Söyler, N. M. Lohan, B. Özkal, D. Chicet, A. David, L.-G. Bujoreanu, Mechanical alloying effects on the thermal behaviour of a Fe-Mn-Si-Cr-Ni shape memory alloy under powder form, Optoelectronics and Advanced Materials-Rapid Communications, 5(5), 2011.

* Soyler A. Umut; Ozkal Burak; Bujoreanu Leandru G., Sintering Densification and Microstructural Characterization of Mechanical Alloyed Fe-Mn-Si based Powder Metal System, TMS 2010 Annual Meeting Supplemental Proceedings on Materials Processing and Properties, TMS 2010 139TH ANNUAL MEETING & EXHIBITION - SUPPLEMENTAL PROCEEDINGS, VOL 3: GENERAL, 2010.

* L. G. Bujoreanu, N. M. Lohan, B. Pricop, N. Cimpoeşu, Thermal memory degradation in a Cu-Zn-Al shape memory alloy during thermal cycling with free air cooling, Springer, Journal of Materials Engineering and Performance, 20(3), 2011.

* B. Pricop, U. Söyler, R. I. Comaneci, B. Özkal, L. G. Bujoreanu, Mechanical cycling effects at Fe-Mn-Si-Cr-Ni SMAs, Manfred Kohl and Volodymyr Chernenko, Physics Procedia, 10, 2010.

* C. Lohan, B. Pricop, R. I. Comãneci, N. Cimpoeşu, L.-G. Bujoreanu, Variation tendencies of tensile constrained recovery behaviour and associated structural changes during thermal cycling of a Fe-Mn-Si-Cr-Ni shape memory alloy, INOE Publishing House, Optoelectronics and Advanced Materials-Rapid Communications, 4(6), 2010.

* Leandru-Gheorghe Bujoreanu, Marcus L. Young, Susanne Gollerthan, Christoph Somsen, Gunther Eggeler, Influence of heat treatment and microstructure on the tensile pseudoelastic response of an Ni-rich NiTi shape memory alloy, International Journal of Materials Research, 101(5), 2010.

* L. G. Bujoreanu, S. Stanciu, B. Özkal, R. I. Comãneci, M. Mayer, Comparative study of the structures of Fe-Mn-Si-Cr-Ni shape memory alloys obtained by classical and by powder metallurgy, respectively, EDP Sciences, P. ©ittner, L. Heller and V. Paidar, ESOMAT 2009 - The 8th European Symposium on Martensitic Transformations, DOI:10.1051/esomat/200905003, 2009.

* S. Stanciu, L. G. Bujoreanu, R.I.Comãneci, N. Cimpoeşu, I. Ioniţã, V.V.Moldoveanu, Particularities of phase transitions in thermomechanically processed Cu-Al-Mn shape memory alloys, EDP Sciences, P. ©ittner, L. Heller and V. Paidar, ESOMAT 2009 - The 8th European Symposium on Martensitic Transformations, DOI:10.1051/esomat/200905004, 2009.

* L.G.Bujoreanu, Formation of transitory bainite as a precursor of alpha-phase during tempering of mastensitic Cu-Zn-Al SMAs, Nova Science Publishers, H.R. Chen (Editor), Shape Memory Alloys: Manufacture, Properties and Applications, ISBN 978-1-60741-789-7, 2010.

* Leandru G. Bujoreanu, Sergiu Stanciu, Radu I. Comaneci, Markus Meyer, Vasile Dia, and Ciprian Lohan, Factors Influencing the Reversion of Stress-induced Martensite to Austenite in a Fe-Mn-Si-Cr-Ni Shape Memory Alloy, Springer, Journal of Materials Engineering and Performance, 18(5-6), 2009.

* S. STANCIU, L.-G. BUJOREANU, N. CIMPOESU, I. IONIÞÃ, V. MOLDOVEANU, Shape memory effect and related characteristics of helical springs made from Cu–Al–Ni alloy by investment casting, Inoe, OPTOELECTRONICS AND ADVANCED MATERIALS – RAPID COMMUNICATIONS, Vol. 3, No. 6, June, 2009.

* M.Susan, L.G.Bujoreanu, D.G.Galusca, C.Munteanu, V.Iliescu, Influence of the relative deformation rate on tube processing by ultrasonic vibration drawing, CENIM, Revista de Metalurgia de Madrid, 40, 2004.

* D.Mihai and L.G.Bujoreanu, Mechanical properties degradation in a Cr-Mo low-alloy steel pipe after prolonged use for gas transport in a power plant station, CENIM, Revista de Metalurgia de Madrid, 38(6), 2002.

* M. Susan, L. Gh. Bujoreanu, D. G. Galusca, C. Munteanu, M. Mantu, ON THE DRAWING IN ULTRASONIC FIELD OF METALLIC WIRES WITH HIGH MECHANICAL RESISTANCE, INOE, Journal of Optoelectronics and Advanced Materials, Vol. 7, No. 2, April, 2005.

* Takahiro Sawaguchi, Leandru-Gheorghe Bujoreanu, Takehiko Kikuchi, Kazuyuki Ogawa, Motomichi Koyama and Masato Murakami, Mechanism of reversible transformation-induced plasticity of Fe-Mn-Si shape memory alloys, Elsevier, Scripta Materialia, 59(8), 2008.

* L.G.Bujoreanu, V.Dia, S.Stanciu, M.Susan, C.Baciu, Study of the tensile constrained recovery behavior of a Fe-Mn-Si shape memory alloy, EDP Sciences, Springer Verlag, European Physical Journal. Special Topics, 158, 2008.

* M. SUSAN, L.-G. BUJOREANU, C.L. DUMITRACHE, L.C.HANGANU, C.BACIU, A kinematical study of ultrasonic welding based on a, INOE, JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, Vol. 10, No. 6, June, 2008.

* S. STANCIU, L.-G. BUJOREANU, BURAK ÖZKAL, M. LUTFI ÖVEÇOGLU, ANDREI VICTOR SANDU, Study of precipitate formation in Cu-Al-Ni-Mn-Fe, JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, Vol. 10, No. 6, June, 2008.

* L.-G. BUJOREANU, S. STANCIU, A. ENACHE, C. LOHAN, I. RUSU, Influence of some extrinsic factors on the two way shape, INOE, JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, Vol. 10, No. 3, March, 2008.

* M.Susan and L.G.Bujoreanu, The metal-tool contact friction at the ultrasonic vibration drawing of ball-bearing steel wires, Centro nacional de Investigaciones Metalurgicas, Revista de Metalurgia de Madrid, 35(6), 1999.

* T. Sawaguchi, L.-G. Bujoreanu, T. Kikuchi, K. Ogawa, F. Yin, Effects of Nb and C in solution and in NbC form on the transformation-related internal friction of Fe-17Mn (mass%) alloys, ISIJ International, Vol. 48, No. 1, 2008.

* V. Dia, L.G. Bujoreanu, S. Stanciu and C. Munteanu, Study of the shape memory effect in lamellar helical springs made from Cu-Zn-Al shape memory alloy, Elsevier, Materials Science and Engineering: A, 481-482, 2008.

* S. Stanciu and L.G. Bujoreanu, Formation of beta1 prime stress-induced martensite in the presence of gama 2-phase, in a Cu-Al-Ni-Mn-Fe shape memory alloy, Elsevier, Materials Science and Engineering: A, 481-482, 2008.

* Leandru-Gheorghe Bujoreanu, On the influence of austenitization on the morphology of alpha-phase in tempered Cu-Zn-Al shape memory alloys, Elsevier, Materials Science and Engineering A, 481-482, 2008.

* L.G. Bujoreanu,M.L. Craus, S. Stanciu, V. Dia, Thermally and stress induced changes in three phase structure of Cu-Zn-Al-Fe shape memory alloy, Institute of Materials, Mark Hull, Andrew Meredith, Susannah Kabel, Materials Science and Technology, 16, No 6, June,, 2000.

* L. G. Bujoreanu, M. L. Craus, I. Rusu, S. Stanciu and D. Sutiman, On the ß2 to a-phase transformation in a Cu-Zn-Al-based shape memory alloy, Elsevier, K.H.J. Buschow, Journal of Alloys and Compounds, Volume 278, Issues 1-2, 1 August, 1998.